A German metrology research institute has developed a solution which enables efficient measurements of strong curved spherical segments which are often used in optical measurement equipment. Currently measurements of the radius of spherical segments are limited by the thermal expansion of the measuring device which has a very high factor which limits the uncertainty. The research institute is searching for licensees.
A German national research institute active in metrology has developed a measurement process, which enables the efficient measurements of strong curved spherical segments which are often used in optical measurement equipment. Measurement uncertainties due to thermal expansion of the measurement equipment are reduces by at least factor 2.
The method uses an interferometer signal coming from the front onto the spherical surface to be measured. In the center (on the optical axis) a phase value is determined, which is determined down to half a wavelength (typically the wavelength is 632 nm). The number of full wave-packets is not given, but can be determined if the distance R would be known to be < 300 nm (about half the wavelength). However, the information is available with such accuracy, because the radius measurements are known via the DMI at 200 nm (k=2), which is measured from behind, even if temperature influences falsify this information.
The measurement of spherical lenses is a cornerstone of optical metrology, but constant improvements in accuracy are still the subject of current R&D. The economic aspect is that a significant improvement in accuracy can be achieved by using existing measuring instruments in a changed usage. The described procedure can be implemented relatively "easy" for measurement system manufacturers by integrating new software. In addition, it is possible to replace the rear DMI interferometer by more cost-effective measuring systems.
- Specific area of activity of the partner: The research institute is searching for international licensees interested in a commercial exploitation of the patented method to increase third party funding. Targeted partners are industrial companies active as measurement system manufacturers and companies active in software development for measurement processes.
The offered systems enables the following advantages compared with state of the art measurement scenarios:
- Measurements of stronger curved surfaces are enabled
- Radius measurement of sphere sections is possible
- reduced measurement uncertainty by at least factor 2 is achieved.
No investments in new equipment are necessary, just the software has to be changed.
Available for demonstration
Patents granted - Patent granted in Germany